Process of refining gasoline produced by cracking



, a e m t m TENT orrica burgh, Pal, asslgnors to Gui! RefiningCompany,"rlttsburgh, Pa., a corporation of Texas No ApplicationSeptember 19 1981; Serial No. sauce 1 v y 11 Chm; (CL 196-44) Thisinvention relates to processes '0! refining being processed, but do noteflect tar-going petroleum distillates produced by cracking, and changesin the boiling points of the material being particularly to thetreatment of such a distillate processed. The term refining, as usedherein,

to reduce its tendency to term and deposit gum is not intended toinclude cracking processes, hy- 1 I in storage receptacles and internalcombustion -drogenation, etc.

engines. More particularly it relatestothe treat- A pressure stilldistillate containing a prement of such a distillate with a small amountof ponderance of gasoline and produced by that type anhydrous aluminumvchlorid, advantageously of process which is commercially known as aliqbetween three per cent and about one-half of one uid phase process ismost advantageously treated 10 per cent, the treatment being conductedat atemwith one-half of one per cent of anhydrous aluperature of about150 C. to 400 C. and under minum chlcrid at a pressure or 1000 poundsper 'a pressure of about 1000 to 2000 pounds per square square inch andat a temperature in the neighborinch, said treatment being continued fora period hood of 400 C. Higher pressures result in an un-- 01 from twominutes to twenty minutes. necessarily'great loss of material bypolymerizall The major portion ofthe gasoline and higher tion and lesseffective removal of existing gum l5 boiling distillates, suchaskerosene, produced in and preclusion of subsequent gum. A temperav theUnited Statestoday is made bycracking, and ture in the neighborhood of400 C. is the most such distillates so produced are characterized bydesirable. Much lower temperatures, while efa tendency to deposit gum instorage vessels. The fective in removing the gum, are accompanied bygasoline deposits gum on the valves and in the great polymerizationlossesof the distillate being 20 cylinders of the engines in which it isused. treated, and about 150 -C. is in most cases the Similarly suchdistillates are, in most cases, charminimum. Temperatures much in'excessof 400 acterized by undesirably high sulfur content. C. are accompaniedby a prohibitive loss in the Common modes of refining these distillatessubform of gas. When there is excessive conversion stantially reduce thegum-Iorming tendency as the temperature is lowered but ordinarily notbe- 25 of the time at which it is treated, but from that low 150' C. Thelosses resulting from polymerimoment there is a continuing tendency toform zation are similarly great when the time of and deposit additionalgum and this subsequenttreatment substantially exceeds twenty minutes,1y formed gum accumulates in substantial quanwhile a treatment ofsubstantially less than two titles in the containersin which thedistillates are minutes is ordinarily unproductive of suflicient 30kept. Gum content is objectionable largely beeffect. H A

cause a considerable portion-of the gum which The effectiveness of ourprocessis well demonforms subsequent to original treatment depositsstrated by the treatment of a liquid phase distilon the hot portionsofthe engine in which it is late which originally had a gum number of 350used and with which it comes in contact, these by the well known copperdish method or measur- 35 deposits in the case of gasoline beingcommonly ing present tendency to deposit gum, and a gum most marked onthe engine valves, on the piston number of 1100 by the oxygen methodcommonly heads, and in the cylinders. Capacity 01' a gasused to measurepotential gum. This so-called oline to presently deposit gum isdetermined by potential gum is non-existent as gum at the time 4 thewell known copper dish test, and ultimate or making the test but thetest isapresent measure 40 capacity of a gasoline to deposit gum ismeasured of the probable ultimate gum formation which by the similarlywellknown oxygen gum test. will accompany indefinite ageing of thegasoline. This ultimate capacity to form gum is commonly On treating thedescribed distillate for two minreierred to as potential gum). utes withone-half of one per cent of anhydrous By our invention we provide amethod of realuminum chlorid, at a temperature of 400 C. 45 fining whichremoves most of the existing gum and under a pressure of 1000 poundsabove atmoscontent and so reacts with the various c'onstitupheric, theformer gum number of 350 by the ents oi the material under treatment asto greatly copper dish method was reduced to 62 and the reduce thetendency to subsequently generate adformer gum number of 1100 by theoxygen meth- W ditional gum, which removes sulfur, and which od wasreduced to 60'; and this improvement in stabilizes the material as tooxidation and color the quality of the product was eflected with achange. The term refining is used herein as. polymerization loss of only8 per cent. 7 general term descriptive of steps in the prepara- In thetreatment of distillates produced by tion of the ilnal product whichimprove the chemthose processes which are commercially known ical andphysical characteristics 01' the material as vapor phase processes wefind it desirable to inproduced by catalytic action.

crease the pressure to the neighborhood of 2000 pounds per square inch.The effectiveness of our treatment on such a material is welldemonstrated by actual treatments whereby we have reduced the copperdish gum number of a distillate from 540 to 3 and its oxygen gum numberfrom 500 to 10, this result being accomplished with polymerization lossof only 10 per cent.

We find that our process can be successfully practiced either in anautoclave or in a continuously operating tubular heating apparatus.

Anhydrous zinc chlorid,,nickel chlorid and anhydrous ferric chlorid arefound to be useful in our process, but we prefer anhydrous aluminumchlorid and we usually employ one-half of one per cent, although we haveused as high as three per cent with success, the temperature beingcontrolled to prevent substantial conversion into lower boilingproducts.

In the ensuing claims the term cracked distillate is used to include allpetroleum cracking still products having a substantial portion ofconstituents boiling within kerosene and gasoline boiling point range,whether or not these constituents have yet been separated fromconstituents of other boiling points. By the term simple thermalcracking process we mean a process wherein cracking is pyrolytic, incontrast to that The terms high pressures? or high superatmosphericpressures" employed in the claims have the significance which isconventional in this art. High pressures have been defined, for example,as ranging between about 600 and 1500 pounds per square inch. The termmetallic chlorid catalyst is used to include those metal chlorids which,like aluminum chlorid, have been recognized by the art as useful inremoval of undesirable constituents from a given distillate by so-calledcondensation. These catalysts are characterized by the fact that thecontained chlorin is loosely held by the metal in contradistinction tochlorids of strongly basic metals. Among the recognized metallic chloridcatalysts are zinc chlorid, nickel chlorid, ferric chlorid and aluminumchlorid.

What we claim is:

1. In the manufacture of a motor fuel from a cracked gasolinedistillate, the refining process which comprises mixing approximatelyfrom onehalf 01' one per cent to three per cent by weight of anhydrousaluminum chlorid with the distillate and heating this mixture toapproximately 400 0., and maintaining it at that temperature under apressure of the order of one thousand to two thousand pounds per squareinch for a period not substantially greater than twenty minutes; thesaid distillate being of such type that substantially no conversiontakes place during the treatment specified.

2. In the manufacture of a motor fuel from a cracked gasolinedistillate, the refining process which comprises mixing approximatelyone-half of one per cent by weight of anhydrous aluminum chlorid withthe distillate and heating this mix ture to approximately 400 C., andmaintaining it at that temperature under a pressure of the order of onethousand to two thousand pounds per square inch for a period notsubstantially less than two minutes or substantially greater than twentyminutes; the said distillate being of such type that substantially noconversion takes place during the treatment specified.

3. The process of refining cracked gasoline distillate from a so-calledliquid phase cracking process which comprises mixing approximately fromone-half of one per cent to three per cent of anhydrous aluminum chloridwith the distillate and heating this mixture to approximately 400 C. andmaintaining it at that temperature under a pressure of the order of onethousand pounds per square inch for a period not substantially greaterthan twenty minutes; the said distillate being of such type thatsubstantially no conversion takes place during the treatment specified.

4. The process of refining a cracked gasoline distillate froma so-calledliquid phase cracking process which comprises mixing approximately fromone-half of one per cent to three per cent of anhydrous aluminum chloridwith the distillate and heating this mixture to approximately 400 C. andmaintaining it at that temperature under a pressure of the order of onethousand pounds per square inch for a periodnot substantially less thantwo minutes or substantially greater than twenty minutes; the saiddistillate being of such type that substantially no conversion takesplace during the treatment specified.

5. The process of refining a cracked gasoline distillate from aso-called vapor phase cracking process which comprises mixing a smallamount of anhydrous aluminum chlorid with the distillate and heating themixture for a short period of the order of two to twenty minutes totemperatures above 150 C. but not exceeding 400 C while maintaining itunder a pressure of the order of two thousand pounds per square inch;the said distillate being of such type that substantially no conversiontakes place during the treatment specified;

6. The process of refining a cracked gasoline distillate from aso-called vapor phase cracking process which comprises mixingapproximately from one-half of one per cent to three per cent ofanhydrous aluminum chlorid with the distillate and heating this mixtureto approximately 400 C. and maintaining it at that temperature under apressure of the order of two thousand pounds per square inch for aperiod not substantially greater than twenty minutes; the saiddistillate being of such type that substantially no conversion takesplace during the treatment specified.

"I. The process of refining a cracked gasoline distillate from aso-called vapor phase cracking process which comprises mixingapproximately from one-half of one per cent to three per cent ofanhydrous aluminum chlorid with the distillate and heating this mixtureto approximately400 C. and maintaining it at that temperature under apressure of the order of two thousand pounds per square inch for aperiod not substantially less than two minutes or substantially greaterthan twenty minutes; the said distillate being of such type thatsubstantially no conversion takes place during the treatment specified.

8. The process of making a motor fuel by refining an unsaturated crackedgasoline distillate derived from a simple thermal cracking process whichcomprises mixing approximately from one-half of one per cent to threeper cent by weight of anhydrous aluminum chlorid with a liquid crackedgasoline distillate and heating this mixture for a short period of theorder of two to twenty minutes to temperatures above 150 C. but notsubstantially exceeding 400 C. while maintaining it in substantiallyliquid phase under high superatmospheric pressures ranging up to about2000 pounds per square inch; the said distillate being of such type thatsubstantially no 0 2,002,950 conversion takes place during the treatmentspecified.

9. The process of claim 8 in which approximately one-half of one percent of aluminum chlorid is used.

10. The process of claim 8 in which a temperature around 400 C. is used.7

11. In the manufacture of motor iuels from cracked gasoline distillatesderived from simple thermal cracking processes, the process whichcomprises mixing a liquid cracked gasoline distillate with from one-halfto three per cent of a metallic chlorid catalyst, heating the mixture totemperatures above 150 C. but not substantially exceeding 400 C. for aperiod not substantially exceeding 20 minutes and under high pressureranging from about 1000 to 2000 pounds per square inch, the saiddistillate being of such type that substantially no conversion takesplace during the treatment specified.

CLARION R. PAYNE. DONALD E. STEVENS.

